CA1289364C - Method for melting and reducing chrome ore - Google Patents
Method for melting and reducing chrome oreInfo
- Publication number
- CA1289364C CA1289364C CA000522788A CA522788A CA1289364C CA 1289364 C CA1289364 C CA 1289364C CA 000522788 A CA000522788 A CA 000522788A CA 522788 A CA522788 A CA 522788A CA 1289364 C CA1289364 C CA 1289364C
- Authority
- CA
- Canada
- Prior art keywords
- molten metal
- vessel
- chrome ore
- gas
- pressure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 title claims abstract description 52
- 238000000034 method Methods 0.000 title claims abstract description 35
- 238000002844 melting Methods 0.000 title claims abstract description 10
- 230000008018 melting Effects 0.000 title claims abstract description 10
- 229910052751 metal Inorganic materials 0.000 claims abstract description 49
- 239000002184 metal Substances 0.000 claims abstract description 49
- 239000007789 gas Substances 0.000 claims abstract description 38
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims abstract description 18
- 238000006243 chemical reaction Methods 0.000 claims abstract description 18
- 229910001882 dioxygen Inorganic materials 0.000 claims abstract description 18
- 239000003575 carbonaceous material Substances 0.000 claims abstract description 14
- 230000003247 decreasing effect Effects 0.000 claims abstract description 13
- 238000007664 blowing Methods 0.000 claims abstract description 10
- 238000003756 stirring Methods 0.000 claims abstract description 10
- 229910052786 argon Inorganic materials 0.000 claims description 13
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 7
- 229910052799 carbon Inorganic materials 0.000 claims description 7
- 239000007787 solid Substances 0.000 claims 1
- 239000000843 powder Substances 0.000 abstract description 4
- 239000000463 material Substances 0.000 abstract description 3
- GRYSXUXXBDSYRT-WOUKDFQISA-N (2r,3r,4r,5r)-2-(hydroxymethyl)-4-methoxy-5-[6-(methylamino)purin-9-yl]oxolan-3-ol Chemical compound C1=NC=2C(NC)=NC=NC=2N1[C@@H]1O[C@H](CO)[C@@H](O)[C@H]1OC GRYSXUXXBDSYRT-WOUKDFQISA-N 0.000 abstract 1
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 22
- 229910052804 chromium Inorganic materials 0.000 description 12
- 239000011651 chromium Substances 0.000 description 12
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 8
- 230000009467 reduction Effects 0.000 description 8
- 239000000571 coke Substances 0.000 description 7
- 239000003245 coal Substances 0.000 description 5
- 239000002893 slag Substances 0.000 description 5
- 239000000292 calcium oxide Substances 0.000 description 4
- 235000012255 calcium oxide Nutrition 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 2
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000011946 reduction process Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 230000008901 benefit Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- -1 for example Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000012254 powdered material Substances 0.000 description 1
- 230000036647 reaction Effects 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B34/00—Obtaining refractory metals
- C22B34/30—Obtaining chromium, molybdenum or tungsten
- C22B34/32—Obtaining chromium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B5/00—General methods of reducing to metals
- C22B5/02—Dry methods smelting of sulfides or formation of mattes
- C22B5/10—Dry methods smelting of sulfides or formation of mattes by solid carbonaceous reducing agents
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Manufacture Of Iron (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
Abstract of the Disclosure A method for melting and reducing chrome ore, which comprises charging chrome ore and carbonaceous material, and blowing in oxygen gas under a pressure ranging from 1 to 600 Torr, while molten metal is being stirred by a stirring gas blown in. In this method, a reaction ves-sel capable of allowing top blowing and bottom blowing onto the molten metal and decreasing pressure within the vessel is employed. Chrome ore and carbonaceous materi-al can be used in the form of lumps or powder. When powdered ore and material are used, they can be injected through a lance or a tuyere into the vessel.
Description
~;28~3G~
The present invention relates to a method for melt-ing and reducing chrome ore, and more particularly, to a method for melting and reducing chrome ore by charging in chrome ore and carbonaceous material, and blowing oxy-gen gas onto the molten metal.
Recently, various methods for melting and reducing chrome ore have been proposed. Japanese Patent Laid Open No. 159963/84, for example, describes a method whersin:
(a) Powder of chrome oxides is injected by carrier-oxidizing gas being blown onto the molten metal;
(b) Carbonaceous material, for example, coal or coke, and gases for stirring, are supplied; and (c) Through the process of reduction, achieved in steps (a) and (b), molten metal containing less than 40%
by weight of chromium is produced.
This method, however, is disadvantageous in that it takes much time to obtain molten metal containing the desired percentage of chromium, since chrome ore is, by nature, hard to reduce.
It is an object of the present invention to provide a method for melting and reducing chrome ore in a high speed.
In order to achieve the above-mentioned object, a method is provided, for melting and reducing chrome ore, by employing a reaction vessel capable of allowing top blowing and bottom blowing onto molten metal and de-creasing pressure inside the reaction vessel, comprising ' 8~1~6a~
the steps of:
supplying molten metal into the vessel;
charginq chrome ore into the vessel;
charging carbonaceous material into the vessel;
decreasing the pressure therein to less than the atmospheric pressure, and blowing oxygen gas onto the molten metal while the molten metal is being stirred by a gas being introduced through a tuyere at the bottom of the vessel.
This invention can be more fully understood from the following detailed description when taken in con-junction with the accompanying drawings, in which:
Fig. 1 is a schematic view showing an example of equipment employed for carrying out a method for melting and reducing chrome ore according to the present inven-tion;
Fig~ 2 is a schematic view showing an example of experimental equipment for performing another example of the method;
Fig. 3 is a graphical representation showing the operation progress of Example 1 of the method;
Fig. 4 is a graphical representation showing the operation progress of Example 2 of the method; and Fig. 5 is a graphical representation showing each change of chrome content, carbon content, and temperature, in relation to time.
Fig. 1 is a schematic view showing an example of equipment ernployed for a method for rnelting and reducing chrome ore, according to the present invention. Molten metal 7 is first supplied into reaction vessel 1. The pressure inside the vessel is decreased to 1 to 600 Torr, by use of a device 4 for exhausting gases. The decreas-ed pressure is maintained. Lumps of chrome ore, of coal, and of flux are charged in through upper hopper 5 and lower hopper 6, onto the molten metal. Argon gas is blown in through tuyere 3. Oxygen gas is blown through lance 2 onto the molten metal, while the molten metal is being stirred by the argon gas. A portion of carbon contained in the charged lumps of coal produces CO gas, another portion dissolves into the molten metal, and the balance remains contained in slag. Thus, chrome ore is reduced by the reaction of the carbon contained in the molten metal and in the slag.
The reduction of chrome ore proceeds in accordance with the following formula:
Cr2O3 + 3C + 2Cr + 3CO
According to the present embodiment, since a de-creased pressure or vaccum is maintained within rea-ction vessel 1, CO gas generated in the reduction process of chrome ore is removed from the vessel. Consequently, the reaction of the reduction is accelerated by this removal of gas. If the pressure is 600 Torr or less, it is effective for the reaction. If it is 300 Torr or less, it is even more effective. However, if it is ~2~
less than 1 Torr, this radically raises the cost of investment in the equipment related to production on a commercial scale. Therefore, 1 to 600 Torr is appro-priate, and 1 to 300 Torr more preferable.
In addition to the advantage of acceleration of the reaction according to the present invention, the reaction time thus shortened by the acceleration there-by reduces the stress on the equipment; the method of present invention can therefore extend the life of the equipment.
In the present embodiment, lumps of chrome ore are used. Chrome ore in powdered form can be used instead, wherein supplying the powder through lance 2 or tuyere 3 is deemed desirable. As another method charging the lumps of chrome ore through the upper part of reaction vessel 1 and also injecting the powdered chrome ore through lance 2 or tuyere 3 can be employed.
Lumps of coal are used as carbonaceous material, in the present embodiment. Lumps of coke, or powdered coal or coke can be substituted therefor. Charging of the lumps through the upper part of the vessel, and injecting of the powdered material through lance 2 or tuyere 3 is recommended. Moreover, to employ both the methods of charging the lumps through the upper part of the vessel and injecting the powder through lance 2 or tuyere 3 can be considered as an alternative method of supplying the carbonaceous material. The optimum amount of oxygen gas to be supplied ranges from 1.0 to 5.0 Nm3/minute-T, where T represents one ton of molten metal. If the amount of oxygen gas supplied is more than 5.0 Nm3/minute~T, more massive, and thus expensive equipment is required. On the other hand, if it is less than 1.0 Nm3/minute-T, the speed of the reduction pro-cess becomes slow, and the amount of heat produced by combustion of the carbonaceous material becomes insuf-ficient.
In the present embodiment, oxygen gas is blown in through the lance. Alternatively, it can be supplied through the tuyere, which has also the effect of stir-ring the molten metal. Moreover, oxygen gas can be blown in through both the lance and the tuyere.
Argon gas is blown in through the bottom, for stirring the molten metal, in the present embodiment.
In place of argon gas, N2 gas, CO2 gas, or the process gas generated in the vessel during the melting and re-ducing reaction can be used. The appropriate amount of gas blown in through the bottom ranges from 0.1 to 1.5 Nm2/minute-T. As the pressure decreases to close to 1 Torr, the gas necessary for stirring can be of a smaller amount. On the other hand, as the pressure becomes close to 600 Torr, a greater amount of gas is required. If, even in a low-pressure atmosphere (from 500 to 600 Torr), the amount of the gas blown in is more than 1.5 ~lm3/minute-T, this quantity is so excessive 9;:~fi4 that a so~called hold-up phenomenon occurs wherein reacting molten metal is ejected out of the reaction vessel.
The present inven-tion will be understood more readi-ly with reference to the following examples; however,these examples are intended to illustrate the present invention and are not to be construed as limiting the scope thereof.
Example l Fig. 2 illustrated schematically an example of experimental equipment employed for one example of the present invention. The equipment is composed of reactor 11 accommodated in vacuum vessel lO which is connected with a device 14 for exhausting gases, so as to remove the gas from inside the reactor. The vaccum vessel con-sists of upper and lower parts; the upper part is equip-ped with a pipe leading to the device, and with inlet 15 for charging material; a gap between the upper and the lower parts is tightly sealed by sealing tool 16. Thus, the experimental equipment forms a tightly sealed sys-tem.
In this experiment, molten metal containing 5% car-bon and 1.2% silicon was used; lumps of chrome ore, of coke, and of burnt lime were charged through inlet 15;
oxygen gas was blown in through lance 2; and argon gas for stirring was injected through porous plug 13 provid-ed at the bottom of the reactor.
1~39~64 The operation progress of the example will now be described with reference to Fig. 3. The operation pro-ceeded in 6 steps to a6.
al: 40 kgs. of molten metal was supplied at the start;
a2: 1 kg. (25 kgs./T) of burnt lime and 2 kgs.
(50 kgs./T) of coke were charged in 2 minutes after the start;
a3: Molten metal 17 was heated and molten slag was produced in the state wherein oxygen gas of 150 NQ/min. (3.75 Nm3/min.-T) and argon gas of 30 NQ/min. (0.75 Nm3/min.-T) were introduced onto the molten metal, under a pressure de-creased to 200 Torr for 3 minutes after the lapse of 17 minutes;
a4: 2 kgs. (50 kgs./T) of chrome ore was charged in 28 minutes after the start;
a5: Chrome ore was reduced in the state wherein oxygen gas of 150 NQ/min. (3.75 Nm3/min.-T) and argon gas of 20 to 50 NQ/min. (0.5 to 1.25 Nm3/min.-T) were introduced onto the molten metal, under a pressure again decreased to 200 Torr for 8 minutes after the lapse of 29 minutes; and a6: The reduced metal was tapped out in 52 minutes after the start.
In the operation, the 8-minute reducing reaction increased the chromium content in the molten metal by 0.32%; the chromium content increased 0.04% per minute.
The carbon content was almost constant throughout the operation, and the silicon content fell to a minute trace.
Example 2 The operation of another example according to the present invention was carried out, employing the same experimental equipment and the same molten metal as in Example 1.
The operation progress of the example will now be described with reference to Fig. 4. The operation pro-ceeded in 6 stages bl to b6.
bl: 40 kgs. of molten metal was supplied at the start;
b2: 1 kg. (25 kgs./T) of burnt lime and 1.5 kgs.
(37.5 kgs./T) of coke were charged in 2 minutes after the start;
b3: Molten metal 17 was heated and molten slag was produced in the state wherein oxygen gas of 150 NQ/min. (3.75 Nm3/min.-T) and argon gas of 50 NQ/min. (1.25 Nm3/min.-T) were introduced onto the molten metal, under an atmospheric pressure of 760 Torr for 6 minutes after the lapse of 3 minutes;
b4: 2 kgs. (50 kgs./T) of chrome ore and 1.5 kgs.
(37.5 kgs./T) of coke were charged in X89;~
12 minutes after the start;
b5: Chrome ore was reduced in the stat0 wherein oxygen gas of 150 to 180 NQ/min. (3.75 to 4.5 Nm3/min.-T) and argon gas of 20 to 50 NQ/min. (0.5 to 1.25 Nm3/min.~T) were introduced onto the molten metal, under the pressure decreased to 200 Torr; and b6: The reduced metal was tapped out in 30 minutes after the start.
In this operation, the 5-minute reducing reaction increased the chromium content in the molten metal by 0.43%; the chromium content increased 0.086% per minute.
The increase in the chromium content of this example was larger than that of Example 1. This is perhaps because the initial temperature of the reduction stage increased by about 50, due to the time for heating the molten metal and producing molten slag having been longer.
In addition to the operation of Example 2 of the present invention, a comparative operation of reduction, with oxygen gas supplied under the same conditions as - in Example 2, except for the atmospheric pressure was carried out. The comparative operation increased the chromium content by 0.15%, or 0.03% per minute. The reduction speed of the comparative operation was so slow as to correspond to about one third of that of Example 2. The reduction speed was considerably slow, even in comparison with that of Example 1.
, . .
1~393~
Example 3 An operation oE one example according to the pres-ent invention, under a pressure decreased to 200 Torr, and another operation, under the atmospheric pressure were carried out, employing the same experimental equip-ment as in the cases of Examples 1 and 2, for comparison of the two operations.
At the beginning, the following materials were charged into reactor 11:
chrome ore; 2 kgs. (50 kgs./T) burnt lime; 1 kg. (25 kgs./T) silica; 1 kg. (25 kgs./T) For the first 5 minutes, chrome ore was reduced under the following conditions:
pressure; 760 Torr (atmospheric pressure) oxygen gas introduced; 150 NQ/min.
(3.75 Nm3/min.-T) argon gas introduced; 10 NQ/min.
(0.25 Nm3/min.-T) and For the subsequent 5 minutes, chrome ore was reduced under the following conditions:
pressure; 200 Torr oxygen gas introduced; 150 NQ/min. (3.75 Nm3/T) argon gas introduced; 10 NQ/min. (0.25 Nm3/T) The result is graphically illustrated in Fig. 5.
~Z89364~
The first 5-minute operation carried out under the atmospheric pressure of 760 Torr increased the chromium content by 0.15%; the chromium content increased 0.03~
per minute. The subsequent 5 minute operation under the pressure decreased to 200 Torr increased the chromium content by 0.5%; the chromium content increased 0.1% per minute. The comparison proves that the reduction, car-ried out at less than the atmospheric pressure, proceed-ed far faster. There was, however, almost no difference to be found with respect to carbon content and tempera-ture in the two comparison operations.
The present invention relates to a method for melt-ing and reducing chrome ore, and more particularly, to a method for melting and reducing chrome ore by charging in chrome ore and carbonaceous material, and blowing oxy-gen gas onto the molten metal.
Recently, various methods for melting and reducing chrome ore have been proposed. Japanese Patent Laid Open No. 159963/84, for example, describes a method whersin:
(a) Powder of chrome oxides is injected by carrier-oxidizing gas being blown onto the molten metal;
(b) Carbonaceous material, for example, coal or coke, and gases for stirring, are supplied; and (c) Through the process of reduction, achieved in steps (a) and (b), molten metal containing less than 40%
by weight of chromium is produced.
This method, however, is disadvantageous in that it takes much time to obtain molten metal containing the desired percentage of chromium, since chrome ore is, by nature, hard to reduce.
It is an object of the present invention to provide a method for melting and reducing chrome ore in a high speed.
In order to achieve the above-mentioned object, a method is provided, for melting and reducing chrome ore, by employing a reaction vessel capable of allowing top blowing and bottom blowing onto molten metal and de-creasing pressure inside the reaction vessel, comprising ' 8~1~6a~
the steps of:
supplying molten metal into the vessel;
charginq chrome ore into the vessel;
charging carbonaceous material into the vessel;
decreasing the pressure therein to less than the atmospheric pressure, and blowing oxygen gas onto the molten metal while the molten metal is being stirred by a gas being introduced through a tuyere at the bottom of the vessel.
This invention can be more fully understood from the following detailed description when taken in con-junction with the accompanying drawings, in which:
Fig. 1 is a schematic view showing an example of equipment employed for carrying out a method for melting and reducing chrome ore according to the present inven-tion;
Fig~ 2 is a schematic view showing an example of experimental equipment for performing another example of the method;
Fig. 3 is a graphical representation showing the operation progress of Example 1 of the method;
Fig. 4 is a graphical representation showing the operation progress of Example 2 of the method; and Fig. 5 is a graphical representation showing each change of chrome content, carbon content, and temperature, in relation to time.
Fig. 1 is a schematic view showing an example of equipment ernployed for a method for rnelting and reducing chrome ore, according to the present invention. Molten metal 7 is first supplied into reaction vessel 1. The pressure inside the vessel is decreased to 1 to 600 Torr, by use of a device 4 for exhausting gases. The decreas-ed pressure is maintained. Lumps of chrome ore, of coal, and of flux are charged in through upper hopper 5 and lower hopper 6, onto the molten metal. Argon gas is blown in through tuyere 3. Oxygen gas is blown through lance 2 onto the molten metal, while the molten metal is being stirred by the argon gas. A portion of carbon contained in the charged lumps of coal produces CO gas, another portion dissolves into the molten metal, and the balance remains contained in slag. Thus, chrome ore is reduced by the reaction of the carbon contained in the molten metal and in the slag.
The reduction of chrome ore proceeds in accordance with the following formula:
Cr2O3 + 3C + 2Cr + 3CO
According to the present embodiment, since a de-creased pressure or vaccum is maintained within rea-ction vessel 1, CO gas generated in the reduction process of chrome ore is removed from the vessel. Consequently, the reaction of the reduction is accelerated by this removal of gas. If the pressure is 600 Torr or less, it is effective for the reaction. If it is 300 Torr or less, it is even more effective. However, if it is ~2~
less than 1 Torr, this radically raises the cost of investment in the equipment related to production on a commercial scale. Therefore, 1 to 600 Torr is appro-priate, and 1 to 300 Torr more preferable.
In addition to the advantage of acceleration of the reaction according to the present invention, the reaction time thus shortened by the acceleration there-by reduces the stress on the equipment; the method of present invention can therefore extend the life of the equipment.
In the present embodiment, lumps of chrome ore are used. Chrome ore in powdered form can be used instead, wherein supplying the powder through lance 2 or tuyere 3 is deemed desirable. As another method charging the lumps of chrome ore through the upper part of reaction vessel 1 and also injecting the powdered chrome ore through lance 2 or tuyere 3 can be employed.
Lumps of coal are used as carbonaceous material, in the present embodiment. Lumps of coke, or powdered coal or coke can be substituted therefor. Charging of the lumps through the upper part of the vessel, and injecting of the powdered material through lance 2 or tuyere 3 is recommended. Moreover, to employ both the methods of charging the lumps through the upper part of the vessel and injecting the powder through lance 2 or tuyere 3 can be considered as an alternative method of supplying the carbonaceous material. The optimum amount of oxygen gas to be supplied ranges from 1.0 to 5.0 Nm3/minute-T, where T represents one ton of molten metal. If the amount of oxygen gas supplied is more than 5.0 Nm3/minute~T, more massive, and thus expensive equipment is required. On the other hand, if it is less than 1.0 Nm3/minute-T, the speed of the reduction pro-cess becomes slow, and the amount of heat produced by combustion of the carbonaceous material becomes insuf-ficient.
In the present embodiment, oxygen gas is blown in through the lance. Alternatively, it can be supplied through the tuyere, which has also the effect of stir-ring the molten metal. Moreover, oxygen gas can be blown in through both the lance and the tuyere.
Argon gas is blown in through the bottom, for stirring the molten metal, in the present embodiment.
In place of argon gas, N2 gas, CO2 gas, or the process gas generated in the vessel during the melting and re-ducing reaction can be used. The appropriate amount of gas blown in through the bottom ranges from 0.1 to 1.5 Nm2/minute-T. As the pressure decreases to close to 1 Torr, the gas necessary for stirring can be of a smaller amount. On the other hand, as the pressure becomes close to 600 Torr, a greater amount of gas is required. If, even in a low-pressure atmosphere (from 500 to 600 Torr), the amount of the gas blown in is more than 1.5 ~lm3/minute-T, this quantity is so excessive 9;:~fi4 that a so~called hold-up phenomenon occurs wherein reacting molten metal is ejected out of the reaction vessel.
The present inven-tion will be understood more readi-ly with reference to the following examples; however,these examples are intended to illustrate the present invention and are not to be construed as limiting the scope thereof.
Example l Fig. 2 illustrated schematically an example of experimental equipment employed for one example of the present invention. The equipment is composed of reactor 11 accommodated in vacuum vessel lO which is connected with a device 14 for exhausting gases, so as to remove the gas from inside the reactor. The vaccum vessel con-sists of upper and lower parts; the upper part is equip-ped with a pipe leading to the device, and with inlet 15 for charging material; a gap between the upper and the lower parts is tightly sealed by sealing tool 16. Thus, the experimental equipment forms a tightly sealed sys-tem.
In this experiment, molten metal containing 5% car-bon and 1.2% silicon was used; lumps of chrome ore, of coke, and of burnt lime were charged through inlet 15;
oxygen gas was blown in through lance 2; and argon gas for stirring was injected through porous plug 13 provid-ed at the bottom of the reactor.
1~39~64 The operation progress of the example will now be described with reference to Fig. 3. The operation pro-ceeded in 6 steps to a6.
al: 40 kgs. of molten metal was supplied at the start;
a2: 1 kg. (25 kgs./T) of burnt lime and 2 kgs.
(50 kgs./T) of coke were charged in 2 minutes after the start;
a3: Molten metal 17 was heated and molten slag was produced in the state wherein oxygen gas of 150 NQ/min. (3.75 Nm3/min.-T) and argon gas of 30 NQ/min. (0.75 Nm3/min.-T) were introduced onto the molten metal, under a pressure de-creased to 200 Torr for 3 minutes after the lapse of 17 minutes;
a4: 2 kgs. (50 kgs./T) of chrome ore was charged in 28 minutes after the start;
a5: Chrome ore was reduced in the state wherein oxygen gas of 150 NQ/min. (3.75 Nm3/min.-T) and argon gas of 20 to 50 NQ/min. (0.5 to 1.25 Nm3/min.-T) were introduced onto the molten metal, under a pressure again decreased to 200 Torr for 8 minutes after the lapse of 29 minutes; and a6: The reduced metal was tapped out in 52 minutes after the start.
In the operation, the 8-minute reducing reaction increased the chromium content in the molten metal by 0.32%; the chromium content increased 0.04% per minute.
The carbon content was almost constant throughout the operation, and the silicon content fell to a minute trace.
Example 2 The operation of another example according to the present invention was carried out, employing the same experimental equipment and the same molten metal as in Example 1.
The operation progress of the example will now be described with reference to Fig. 4. The operation pro-ceeded in 6 stages bl to b6.
bl: 40 kgs. of molten metal was supplied at the start;
b2: 1 kg. (25 kgs./T) of burnt lime and 1.5 kgs.
(37.5 kgs./T) of coke were charged in 2 minutes after the start;
b3: Molten metal 17 was heated and molten slag was produced in the state wherein oxygen gas of 150 NQ/min. (3.75 Nm3/min.-T) and argon gas of 50 NQ/min. (1.25 Nm3/min.-T) were introduced onto the molten metal, under an atmospheric pressure of 760 Torr for 6 minutes after the lapse of 3 minutes;
b4: 2 kgs. (50 kgs./T) of chrome ore and 1.5 kgs.
(37.5 kgs./T) of coke were charged in X89;~
12 minutes after the start;
b5: Chrome ore was reduced in the stat0 wherein oxygen gas of 150 to 180 NQ/min. (3.75 to 4.5 Nm3/min.-T) and argon gas of 20 to 50 NQ/min. (0.5 to 1.25 Nm3/min.~T) were introduced onto the molten metal, under the pressure decreased to 200 Torr; and b6: The reduced metal was tapped out in 30 minutes after the start.
In this operation, the 5-minute reducing reaction increased the chromium content in the molten metal by 0.43%; the chromium content increased 0.086% per minute.
The increase in the chromium content of this example was larger than that of Example 1. This is perhaps because the initial temperature of the reduction stage increased by about 50, due to the time for heating the molten metal and producing molten slag having been longer.
In addition to the operation of Example 2 of the present invention, a comparative operation of reduction, with oxygen gas supplied under the same conditions as - in Example 2, except for the atmospheric pressure was carried out. The comparative operation increased the chromium content by 0.15%, or 0.03% per minute. The reduction speed of the comparative operation was so slow as to correspond to about one third of that of Example 2. The reduction speed was considerably slow, even in comparison with that of Example 1.
, . .
1~393~
Example 3 An operation oE one example according to the pres-ent invention, under a pressure decreased to 200 Torr, and another operation, under the atmospheric pressure were carried out, employing the same experimental equip-ment as in the cases of Examples 1 and 2, for comparison of the two operations.
At the beginning, the following materials were charged into reactor 11:
chrome ore; 2 kgs. (50 kgs./T) burnt lime; 1 kg. (25 kgs./T) silica; 1 kg. (25 kgs./T) For the first 5 minutes, chrome ore was reduced under the following conditions:
pressure; 760 Torr (atmospheric pressure) oxygen gas introduced; 150 NQ/min.
(3.75 Nm3/min.-T) argon gas introduced; 10 NQ/min.
(0.25 Nm3/min.-T) and For the subsequent 5 minutes, chrome ore was reduced under the following conditions:
pressure; 200 Torr oxygen gas introduced; 150 NQ/min. (3.75 Nm3/T) argon gas introduced; 10 NQ/min. (0.25 Nm3/T) The result is graphically illustrated in Fig. 5.
~Z89364~
The first 5-minute operation carried out under the atmospheric pressure of 760 Torr increased the chromium content by 0.15%; the chromium content increased 0.03~
per minute. The subsequent 5 minute operation under the pressure decreased to 200 Torr increased the chromium content by 0.5%; the chromium content increased 0.1% per minute. The comparison proves that the reduction, car-ried out at less than the atmospheric pressure, proceed-ed far faster. There was, however, almost no difference to be found with respect to carbon content and tempera-ture in the two comparison operations.
Claims (14)
1. A method for melting and reducing chrome ore, employing a reaction vessel including a lance disposed above molten metal in said vessel for top blowing and a tuyere disposed at the bottom of the vessel for bottom blowing through the molten metal and pressure means for decreasing pressure within said vessel, which comprises the steps of:
supplying molten metal into said vessel;
charging chrome ore into said vessel;
charging solid carbonaceous material into said vessel to substantially maintain the carbon content in the reaction vessel;
decreasing the pressure within the vessel through said pressure means to less than atmospheric pressure;
and blowing oxygen gas onto said molten metal through the lance while said molten metal is being stirred by a gas which is introduced through the tuyere at the bottom of said vessel.
supplying molten metal into said vessel;
charging chrome ore into said vessel;
charging solid carbonaceous material into said vessel to substantially maintain the carbon content in the reaction vessel;
decreasing the pressure within the vessel through said pressure means to less than atmospheric pressure;
and blowing oxygen gas onto said molten metal through the lance while said molten metal is being stirred by a gas which is introduced through the tuyere at the bottom of said vessel.
2. The method according to claim 1, wherein said step of decreasing the pressure includes decreasing the pressure to 1 to 600 Torr by the pressure means comprising a device for exhausting gases.
3. The method according to claim 2, wherein said step of decreasing the pressure includes decreasing the pressure to 1 to 300 Torr.
4. The method according to claim 1, wherein said step of charging chrome ore includes charging lumps of chrome ore through the upper part of said vessel.
5. The method according to claim 1, wherein said step of charging chrome ore includes injecting powdered chrome ore through a lance at the upper part of said vessel.
6. The method according to claim 1, wherein said step of charging chrome ore includes injecting powdered chrome ore through a tuyere at the bottom of said vessel.
7. The method according to claim 1, wherein said step of charging carbonaceous material includes charging lumps of carbonaceous material through the upper part of said vessel.
8. The method according to claim 1, wherein said step of charging carbonaceous material includes injecting powdered carbonaceous material through said lance.
9. The method according to claim 1, wherein said step of charging carbonaceous material includes injecting powdered carbonaceous material through said tuyere.
10. The method according to claim 1, wherein an oxygen gas is blown in an amount ranging from 1.0 to 5.0 Nm3/min..T, where T represents one ton of molten metal.
11. The method according to claim 1, wherein the gas for stirring said molten metal, introduced through said tuyere includes a gas selected from the group consisting of Ar, N2, and CO2, and in an amount ranging from 0.1 to 1.5 Nm3/min..T, where T represents one ton of molten metal.
12. The method according to claim 1, wherein the gas for stirring said molten metal, introduced through said tuyere includes a gas selected from the group consisting of Ar, N2, and CO2, and in an amount ranging from 0.3 to 1.5 Nm3/min..T, where T represents one ton of molten metal.
13. The method according to claim 1, wherein the gas for stirring said molten metal, introduced through said tuyere includes a gas generated in the reaction within said vessel, and in an amount ranging from 0.1 to 1.5;
Nm3/min..T, where T represents one ton of molten metal.
Nm3/min..T, where T represents one ton of molten metal.
14. The method according to claim 1, wherein the gas for stirring said molten metal, introduced through said tuyere includes a gas generated in the reaction within said vessel, and in an amount ranging from 0.3 to 1.5 Nm3/min..T, where T represents one ton of molten metal.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP252635/85 | 1985-11-13 | ||
| JP25263585 | 1985-11-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1289364C true CA1289364C (en) | 1991-09-24 |
Family
ID=17240093
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000522788A Expired - Lifetime CA1289364C (en) | 1985-11-13 | 1986-11-12 | Method for melting and reducing chrome ore |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4783219A (en) |
| EP (1) | EP0222397B1 (en) |
| JP (1) | JPS62202035A (en) |
| CN (1) | CN86107703A (en) |
| AT (1) | ATE73172T1 (en) |
| CA (1) | CA1289364C (en) |
| DE (1) | DE3684099D1 (en) |
| ZA (1) | ZA868613B (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4780134A (en) * | 1986-09-23 | 1988-10-25 | A. Finkl & Sons Co. | Simplified method and apparatus for treating molten steel |
| US4961784A (en) * | 1987-08-13 | 1990-10-09 | Nkk Corporation | Method of smelting reduction of chromium raw materials and a smelting reduction furnace thereof |
| JPH01165743A (en) * | 1987-09-10 | 1989-06-29 | Nkk Corp | Method for charging of material in melting reduction of ore |
| US4944799A (en) * | 1987-09-10 | 1990-07-31 | Nkk Corporation | Method of producing stainless molten steel by smelting reduction |
| SE466315B (en) * | 1988-01-05 | 1992-01-27 | Middelburg Steel & Alloys Pty | PROCEDURES FOR SULFUR AND SILICON CONTROL IN PRE-CHROME PREPARATION |
| DE3825658A1 (en) * | 1988-07-28 | 1990-02-01 | Hoechst Ag | WATER-SOLUBLE FIBER-REACTIVE DYES, METHOD FOR THEIR PRODUCTION AND THEIR USE |
| DE69010901T2 (en) * | 1989-06-02 | 1994-11-24 | Cra Services | PRODUCTION OF REMOTE ALLOY IN A MELT BATH REACTOR. |
| CA2041297C (en) * | 1991-04-26 | 2001-07-10 | Samuel Walton Marcuson | Converter and method for top blowing nonferrous metal |
| US5112387A (en) * | 1991-08-21 | 1992-05-12 | Instituto Mexicano De Investigaciones Siderurgicas | Producing stainless steels in electric arc furnaces without secondary processing |
| WO1995028507A2 (en) * | 1994-04-08 | 1995-10-26 | Raymond Joseph Sartini | Process for continuous hot dip zinc coating of aluminum profiles |
| CN103836946A (en) * | 2012-11-21 | 2014-06-04 | 虞文娟 | Induction furnace for metal smelting |
| CN103836943B (en) * | 2012-11-21 | 2015-10-14 | 虞文娟 | Induction furnace is blown again in bottom |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3252790A (en) * | 1956-06-27 | 1966-05-24 | Union Carbide Corp | Preparation of metals and alloys |
| BE610265A (en) * | 1960-11-18 | |||
| US3508906A (en) * | 1967-08-30 | 1970-04-28 | Foote Mineral Co | Beneficiation of chromium ore to reduce the iron content |
| DE2007373B2 (en) * | 1970-02-18 | 1973-05-03 | Eisenwerk-Gesellschaft Maximilianshütte mbH, 8458 Sulzbach-Rosenberg | PROCESS AND CONVERTER FOR MANUFACTURING FERRITIC CHROME STEEL |
| BE781241A (en) * | 1971-05-28 | 1972-07-17 | Creusot Loire | REFINING PROCESS FOR ALLIED STEELS CONTAINING CHROME AND MORE SPECIFICALLY STAINLESS STEELS |
| US3854932A (en) * | 1973-06-18 | 1974-12-17 | Allegheny Ludlum Ind Inc | Process for production of stainless steel |
| DE2737832C3 (en) * | 1977-08-22 | 1980-05-22 | Fried. Krupp Huettenwerke Ag, 4630 Bochum | Use of blower nozzles with variable cross-section for the production of stainless steels |
| ZA827820B (en) * | 1981-10-30 | 1983-08-31 | British Steel Corp | Production of steel |
| US4497656A (en) * | 1982-06-23 | 1985-02-05 | Pennsylvania Engineering Corporation | Steel making method |
| DE3442245A1 (en) * | 1984-11-19 | 1986-05-28 | Japan Metals & Chemicals Co., Ltd., Tokio/Tokyo | Process for producing an alloy of high chromium content by smelting reduction |
-
1986
- 1986-11-10 US US06/929,171 patent/US4783219A/en not_active Expired - Fee Related
- 1986-11-11 JP JP61266724A patent/JPS62202035A/en active Pending
- 1986-11-12 CA CA000522788A patent/CA1289364C/en not_active Expired - Lifetime
- 1986-11-12 AT AT86115727T patent/ATE73172T1/en not_active IP Right Cessation
- 1986-11-12 DE DE8686115727T patent/DE3684099D1/en not_active Expired - Fee Related
- 1986-11-12 EP EP86115727A patent/EP0222397B1/en not_active Expired - Lifetime
- 1986-11-13 CN CN198686107703A patent/CN86107703A/en active Pending
- 1986-11-13 ZA ZA868613A patent/ZA868613B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| US4783219A (en) | 1988-11-08 |
| ZA868613B (en) | 1987-07-29 |
| EP0222397B1 (en) | 1992-03-04 |
| EP0222397A2 (en) | 1987-05-20 |
| ATE73172T1 (en) | 1992-03-15 |
| CN86107703A (en) | 1987-06-10 |
| JPS62202035A (en) | 1987-09-05 |
| DE3684099D1 (en) | 1992-04-09 |
| EP0222397A3 (en) | 1989-06-07 |
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